<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    //判断两个数是否相等
    console.log(Math.abs(1 / 3 - (1 - 2 / 3)) < 0.000001)

    // undefined
    var a;
    console.log("a的值为::" + a)


    //null
    var b = false;
    console.log(b);

    // 数组
    var arr = [1, "hello", null, false, true, "hanhan", ["arr2", "arr12"], ["11", "121"]]
    console.log("数组为:" + arr)

    //对象
    var persion = {
        name:"敦佳星",
        age:"三岁",
        height:174,
        like:["钱","钱","还是钱"]

    }
    console.log("对象为"+persion)
</script>

</body>
</html>